Various inventions related to pumps have been proposed. An example of such an invention is “a brushless motor and a pump including the brushless motor, the brushless motor including a cylindrical magnet that is externally coated with resin and a Hall element that detects positions of magnetic poles of the magnet, and generating a rotating magnetic field by applying a current to coils in accordance with a signal from the Hall element that detects the positions of the magnetic poles of the magnet, wherein magnet projections are provided on a Hall-element-side end surface of the magnet” (see, for example, Patent Literature 1).
In this pump, since the magnet projections are provided, the distance between the magnet and the Hall element is reduced. As a result, the magnetic force applied to the Hall element is increased, and does not become insufficient even when the magnet is heated to a high temperature and demagnetized. Consequently, abnormal heating of components of a control unit can be prevented, and normal operation can be continued.